<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .box {
            width: 100px;
            height: 100px;
            background-color: teal;
        }

    </style>
</head>

<body>
    <h1>赖晗是猪</h1>
    <h2>赖晗是猪</h2>
    <h3>赖晗是猪</h3>
    <div class="box">
        
    </div>
    <h4>赖晗是猪</h4>
</body>

</html>